A regulator of this kind introduces pressurized fluid from an inlet port and regulates the pressure thereof to a set point to discharge the fluid from an outlet port. One example thereof is disclosed in U.S. Pat. No. 5,458,001. The regulator comprises a valve seat disposed in a fluid flow path interconnecting the inlet port and the outlet port, a diaphragm movably disposed in the outlet side of the valve seat, a poppet valve connected to the diaphragm for opening and shutting the valve seat from the inlet side by movement of the diaphragm, and a pressure-adjusting spring for urging the diaphragm in the direction that the poppet valve opens the valve seat. The poppet valve opens and shuts the valve seat by an amount of corresponding opening to the acting force difference between the outlet side fluid pressure mutually inversely applied to the diaphragm and the pressure regulating spring force, so that the fluid pressure in the inlet side is reduced to be regulated at a set point.
Since the diaphragm is prone to move not only in the axial direction but also in the direction that the axial line becomes inclined, such regulator has a weakpoint in that the poppet valve connected to the diaphragm is likely to contact and separate from the valve seat in an inclined state thereof so that the opening and shutting operation of the poppet valve is unstable, resulting in the poor accuracy of pressure adjusting. The regulator also has another defect in that localized wear is prone to be produced by contacting and separating from the valve seat of the poppet valve in an inclined state thereof so as to reduce the durability of the regulator.